"Windows XP was the last client version of Windows to include the Pinball game that had been part of Windows since Windows 95. There is apparently speculation that this was done for legal reasons. No, that's not why." I love these stories.

An from reading the article comments, the code was originally written in Pentium-optimized assembly (oh, the days of U/V pipe dreams), and later backported to C (probably with any comments removed?) Good luck trying to maintain that